My 3yo Niece - Thoughts?

[Mezz]

I've never really been interested in shooting portraits, but I've found that I love getting shots of my 3yo niece. If she holds still long enough, that is. My sister wanted to get a few good shots of them together today, and so we went outside and snapped a few. What do you guys think of them?

http://i37.photobucket.com/albums/e82/littlewolfe/My%20Photography/Portraits/IMG_0001.jpg
No flash used.
53mm
1/200
f/5.6
ISO 200

http://i37.photobucket.com/albums/e82/littlewolfe/My%20Photography/Portraits/IMG_0008.jpg
No flash used.
36mm
1/250
f/5.0
ISO 200

I've been playing around with the monochrome setting, and liked how this one turned out.
http://i37.photobucket.com/albums/e82/littlewolfe/My%20Photography/Portraits/IMG_0019.jpg
No flash used.
34mm
1/500
f/4.5
ISO 200

None of the pictures really stuck out to me as amazing, these three are probably my low-end faves. Anyways, what did I do well in these photos? How can I improve for next time?

Thanks for any input!